38 loads in 357 cases ?

rebs · January 9, 2015, 05:23 PM

I have been loading 2.7 gr of bullseye with a 148 gr hollow base wad cutter in 38 spl cases. I would like to start using 357 mag cases because my pistol is a S&W model 19 with 4 inch barrel. The 357 cases will shorten the jump from cylinder to forcing cone and rifling. Also I will only get one set of carbon rings in the chambers.
Would anyone have a good idea what amount of bullseye powder to use in the 357 mag case to be the same as 2.7 bullseye in the 38 cases ?

Nick_C_S · January 9, 2015, 05:41 PM

Quote:

Would anyone have a good idea what amount of bullseye powder to use in the 357 mag case to be the same as 2.7 bullseye in the 38 cases ?

A little more

Heh, I don't have an exact amount unfortunately. But I would guess around 0.3gn more.

Do you have a chronograph?

I load a lot of 38 DEWC's with 2.95gn Bullseye. It's a great round and I use it for IDPA competion (just makes power factor). When I loaded at 2.7gn, I got only 686 fps through a 4" bbl - and that's a little short of IDPA power factor. The shot just fine, but I had to bump it up a little.

At any rate, making the transition to a 357 Mag case means more internal volume, and potentially more inconsistent ignitions. The powder is going to behave like it's slower. You'll need to bump up the recipe.

Personally, I don't care for this practice. But many do it with satisfactory ballistic results - so I'm not discouraging it.

I don't mind the fouling ring in the cylinder.

1: it scrubs out.

2: I usually shoot my 38 ammo in a 38 gun. When I'm shooting my 357's, I generally use 357 power ammunition.

3: The pressure of these above-mentioned rounds are so low, that the gasses blow back from lack of case expansion. So you're going to get cylinder fouling no matter what. Moving to a Magnum case will not solve this condition.

oley55 · January 9, 2015, 05:55 PM

Nick, well said:

3: The pressure of these above-mentioned rounds are so low, that the gasses blow back from lack of case expansion. So you're going to get cylinder fouling no matter what. Moving to a Magnum case will not solve this condition.

**Unclenick** · January 9, 2015, 06:13 PM

The ring that can be an issue is a ring of metal fouling, not powder fouling. Lead from shooting .38 cases sometimes builds to the point you cannot even chamber a .357 round. It can also deteriorate accuracy as it builds. At that point it is squeezing in on the .357 and can raise pressures. Whether or not this happens in your gun depends, I think, mainly on how much gas cutting of the bullet base occurs as it leaves the case. That, in turn, depends in part in how much bigger the chamber throats are than the bullet. The lead cleaning reamers were developed originally to address this problem, back when revolvers were more popular in target matches. The ring can be hard to remove in some guns, making it attractive to avoid making it in the first place, if you can. But even .38 Special chambers will eventually develop them if the conditions are right.

As to the powder difference, check velocity. You would think an increase is automatically indicated, but if you take a look at Hodgdon's data for HP38/231 under a wadcutter, the .38 case actually needs more powder. This is likely due to the primer unseating the bullet in the shorter case before the powder starts building pressure, making the actual bullet position at the pressure peak further forward than when it remains seated during primer firing, as it seems to in the .357 case.

Nick_C_S · January 9, 2015, 06:19 PM

Learn something every day. Thanks Unclenick.

mehavey · January 9, 2015, 06:23 PM

QL tells me what Nick suggested:

Increase from 2.7 to 3.0gr Bullseye to maintain velocity

dahermit · January 9, 2015, 06:44 PM

I use 2.7 Bullseye under 125 grain cast bullets in .38 Spl. cases as my gallery load for my .38 Specials. However, when I used .357 Magnum cases with that same load and bullet, I got some rounds that, although the bullets cleared the barrel, the sound was not a "bang", more of a "puff". When I increased to 3.0 grains of Bullseye in the .357 Magnum cases, the normal, sharp report returned.

As for decreasing bullet jump, I found that in my S&W 686, that I could not find an accurate load until I switched to .357 cases. Others have reported no difference in accuracy between .38 Spl. cases and .357 for target loads, I did and will continue to only use .357 cases in my .357's.

Hammerhead · January 9, 2015, 10:42 PM

I'm sure bumping up .2 or .3 will be fine, but there is data for wadcutters and other light loads in magnum brass. One inexpensive source is the Loadbooks USA book. I wouldn't recommend it as a primary manual, but it has a lot of data you don't find in most books.
http://www.midwayusa.com/product/442...ual?cm_vc=U112

SHR970 · January 9, 2015, 10:45 PM

I won't speak for HBWC's but in general with other bullets I use 38 +P loads to get 30 standard velocities with 357 brass.

January 9, 2015, 05:23 PM	#1
rebs Senior Member Join Date: January 10, 2012 Posts: 3,881	38 loads in 357 cases ? I have been loading 2.7 gr of bullseye with a 148 gr hollow base wad cutter in 38 spl cases. I would like to start using 357 mag cases because my pistol is a S&W model 19 with 4 inch barrel. The 357 cases will shorten the jump from cylinder to forcing cone and rifling. Also I will only get one set of carbon rings in the chambers. Would anyone have a good idea what amount of bullseye powder to use in the 357 mag case to be the same as 2.7 bullseye in the 38 cases ?

January 9, 2015, 06:13 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,060	The ring that can be an issue is a ring of metal fouling, not powder fouling. Lead from shooting .38 cases sometimes builds to the point you cannot even chamber a .357 round. It can also deteriorate accuracy as it builds. At that point it is squeezing in on the .357 and can raise pressures. Whether or not this happens in your gun depends, I think, mainly on how much gas cutting of the bullet base occurs as it leaves the case. That, in turn, depends in part in how much bigger the chamber throats are than the bullet. The lead cleaning reamers were developed originally to address this problem, back when revolvers were more popular in target matches. The ring can be hard to remove in some guns, making it attractive to avoid making it in the first place, if you can. But even .38 Special chambers will eventually develop them if the conditions are right. As to the powder difference, check velocity. You would think an increase is automatically indicated, but if you take a look at Hodgdon's data for HP38/231 under a wadcutter, the .38 case actually needs more powder. This is likely due to the primer unseating the bullet in the shorter case before the powder starts building pressure, making the actual bullet position at the pressure peak further forward than when it remains seated during primer firing, as it seems to in the .357 case. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

January 9, 2015, 06:19 PM	#5
Nick_C_S Senior Member Join Date: March 21, 2013 Location: Idaho Posts: 5,522	Learn something every day. Thanks Unclenick. __________________ Gun control laws benefit only criminals and politicians - but then, I repeat myself. Life Member, National Rifle Association

January 9, 2015, 05:55 PM	#3
oley55 Senior Member Join Date: September 6, 2013 Location: JAX, FL Posts: 377	Nick, well said: 3: The pressure of these above-mentioned rounds are so low, that the gasses blow back from lack of case expansion. So you're going to get cylinder fouling no matter what. Moving to a Magnum case will not solve this condition.

January 9, 2015, 06:23 PM	#6
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,883	QL tells me what Nick suggested: Increase from 2.7 to 3.0gr Bullseye to maintain velocity

January 9, 2015, 06:44 PM	#7
dahermit Senior Member Join Date: October 28, 2006 Location: South Central Michigan...near Posts: 6,501	I use 2.7 Bullseye under 125 grain cast bullets in .38 Spl. cases as my gallery load for my .38 Specials. However, when I used .357 Magnum cases with that same load and bullet, I got some rounds that, although the bullets cleared the barrel, the sound was not a "bang", more of a "puff". When I increased to 3.0 grains of Bullseye in the .357 Magnum cases, the normal, sharp report returned. As for decreasing bullet jump, I found that in my S&W 686, that I could not find an accurate load until I switched to .357 cases. Others have reported no difference in accuracy between .38 Spl. cases and .357 for target loads, I did and will continue to only use .357 cases in my .357's.

January 9, 2015, 10:42 PM	#8
Hammerhead Senior Member Join Date: May 31, 2004 Location: Minnesota Posts: 2,432	I'm sure bumping up .2 or .3 will be fine, but there is data for wadcutters and other light loads in magnum brass. One inexpensive source is the Loadbooks USA book. I wouldn't recommend it as a primary manual, but it has a lot of data you don't find in most books. http://www.midwayusa.com/product/442...ual?cm_vc=U112

January 9, 2015, 10:45 PM	#9
SHR970 Senior Member Join Date: January 24, 2011 Posts: 1,427	I won't speak for HBWC's but in general with other bullets I use 38 +P loads to get 30 standard velocities with 357 brass.